commit e617a34d589ac8ef26203ae90443a0e98f7032b1 Author: Nick Mathewson nickm@torproject.org Date: Tue Jun 21 10:22:54 2011 -0400
Add, use a bufferevent-safe connection_flush()
A couple of places in control.c were using connection_handle_write() to flush important stuff (the response to a SIGNAL command, an ERR-level status event) before Tor went down. But connection_handle_write() isn't meaningful for bufferevents, so we'd crash.
This patch adds a new connection_flush() that works for all connection backends, and makes control.c use that instead.
Fix for bug 3367; bugfix on 0.2.3.1-alpha. --- changes/bug3367 | 4 ++++ src/or/connection.c | 19 +++++++++++++++++++ src/or/connection.h | 2 ++ src/or/control.c | 4 ++-- 4 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/changes/bug3367 b/changes/bug3367 new file mode 100644 index 0000000..8a69778 --- /dev/null +++ b/changes/bug3367 @@ -0,0 +1,4 @@ + o Minor bugfixes + - Fix a crash when handling the SIGNAL controller command or + reporting ERR-level status events with bufferevents enabled. Found + by Robert Ransom. Fixes bug 3367; bugfix on 0.2.3.1-alpha. diff --git a/src/or/connection.c b/src/or/connection.c index 317bfb1..12d93ce 100644 --- a/src/or/connection.c +++ b/src/or/connection.c @@ -3314,6 +3314,25 @@ connection_handle_write(connection_t *conn, int force) return res; }
+/** + * Try to flush data that's waiting for a write on <b>conn</b>. Return + * -1 on failure, 0 on success. + * + * Don't use this function for regular writing; the buffers/bufferevents + * system should be good enough at scheduling writes there. Instead, this + * function is for cases when we're about to exit or something and we want + * to report it right away. + */ +int +connection_flush(connection_t *conn) +{ + IF_HAS_BUFFEREVENT(conn, { + int r = bufferevent_flush(conn->bufev, EV_WRITE, BEV_FLUSH); + return (r < 0) ? -1 : 0; + }); + return connection_handle_write(conn, 1); +} + /** OpenSSL TLS record size is 16383; this is close. The goal here is to * push data out as soon as we know there's enough for a TLS record, so * during periods of high load we won't read entire megabytes from diff --git a/src/or/connection.h b/src/or/connection.h index 94ae645..8dc0112 100644 --- a/src/or/connection.h +++ b/src/or/connection.h @@ -79,6 +79,8 @@ int connection_fetch_from_buf_http(connection_t *conn, int connection_wants_to_flush(connection_t *conn); int connection_outbuf_too_full(connection_t *conn); int connection_handle_write(connection_t *conn, int force); +int connection_flush(connection_t *conn); + void _connection_write_to_buf_impl(const char *string, size_t len, connection_t *conn, int zlib); static void connection_write_to_buf(const char *string, size_t len, diff --git a/src/or/control.c b/src/or/control.c index 5e71a2e..e65cd26 100644 --- a/src/or/control.c +++ b/src/or/control.c @@ -600,7 +600,7 @@ send_control_event_string(uint16_t event, event_format_t which, else if (event == EVENT_STATUS_SERVER) is_err = !strcmpstart(msg, "STATUS_SERVER ERR "); if (is_err) - connection_handle_write(TO_CONN(control_conn), 1); + connection_flush(TO_CONN(control_conn)); } } } SMARTLIST_FOREACH_END(conn); @@ -1257,7 +1257,7 @@ handle_control_signal(control_connection_t *conn, uint32_t len, send_control_done(conn); /* Flush the "done" first if the signal might make us shut down. */ if (sig == SIGTERM || sig == SIGINT) - connection_handle_write(TO_CONN(conn), 1); + connection_flush(TO_CONN(conn));
process_signal(sig);